Mineral fiber paper and process of making the same



Patented Nov. 3, 1931 UNITED STATES PATENT tiara Y ARTHUR L. KENNEDY, OF KEENE, nnwnniv rsrrmn, assreivon T PLASTIC, Inc, A

' conronnrron or new HAMPSHIRE MINERAL FIBER PAPER AND PROCESS OF MAKING THE SAME No Drawing.

My invention relates particularly to a pa per containing a mineral fiber, such, for example, as asbestos or mineral wool, andthe process of making the same, and which has many advantagesover previous papers made from mineral fibers.

The object of my invention is to provide a paper containing a mineral fiber, as, for example, asbestos or mineral Wool, but which has very superior characteristics over previous asbestos papers and similar products, and the obj ectis, also, to provide an advantageous process for the making of the same.

Previously, in the manufacture of ashestos paper it has been found necessary to include therein a large amount of vegetable fiber, the minimum amount of this fiber required being'usually 40%, in order to avoid continual breakage in the web, so as to produce the desired flow of the wet pulp, to pre vent the web sticking to the rolls, and, fur.- thermore, to avoid producing holes and pool:

' marks in the finished papers. Also, in using asbestos papers made in accordance with previous processes, as, for example, in the winding of electric wires and cables, the manufacturer. found it necessary to count upon a very large percentage of loss due to breakage of the paper in the winding operations.

The paper made in accordance with my in e vention does not require the presence of any vegetable fiber whatever, and, furthermore, can be made with a very much larger percentage of asbestos or other mineral fiber. Nevertheless, a paper made in accordance with my invention has a greater strength, takes a much smoother finish, and is very much more flexible than previous asbestos papers. Furthermore, by reason of the increased strength the large percentage of breakages, as in the'use of previous asbestos papers, is avoided, thus materially decreasing the cost of manufacture and the cost of working the paper into manufactured products.

The paper made in accordance with my invention has a wide variety of uses and is espe cially applicable to the winding of electric wires and cables, not only by reason of the small percentage of the breakage, but, also, because of the very high dielectric of the pa- Application filed June 22,

1927. SerialNo. 200,773.

As one example of my invention, 1000 lbs. of

kelp while wet and preferably with the stems removed, which comprises approximately 100 lbs. of solids by dry weight, are mixed with 15 lbs. of soda ash, that is to say, sodium carbonate, or anyother form of alkali; These are ground up in any desired kind of appara j jtus for comminuting the same, such, for instance, as a meatthopperl- To the mass thus obtamed I add a 10% solution of sulphuric acid in water in just suiiicient quantity to neutralize the alkali. This produces a coagulated precipitate which 1s then washed in three wash waters to eliminate the natural mineral salts of the kelp, such asso-dium, potassium, calcium, iodme, bro1n1ne,1ron, and

sulphur compounds. The purpose of this stop is to prevent the subsequent crystallization of these salts in the paper, which would interfere WlL-ll the dielectric of the latter. The water is then removed from the coagulated precipitant, either in a press to form press-cakes, or in a rotary centrifuge, thus obtaining a kelp product ready for. admixture with the mineral fibers. The mineral fibers may be asbestos, mineral wool, or any other desired kind of mineral fiber.

15 lbs. of the kelp product are then mixed with 100 lbs; of, asbestos, using,'preiierably, asbestos fibers, having a length of ,4,{01' more. If desired, however, a fiber shorter than f. length may be used, although the length fibers are preferred. 2% lbs. of sodium carbonateare then added, as Well as gals. of water, and the kelp mixture is'the'n subiectedto the action of a heater to thoroughly mix the same. When they are or, in fact, any other soluble metallic salt that will produce an insoluble compound with the alginic acid of the kelp. The algulose V which is also present may or may not combine in part or wholly with the said salt. The pulp thus formed s then run into an .ord1-'. nary paper making machine, such, for example, as is used in the production of newspaper print or book papers, and which, 1n

general, comprises a web forming part, a drying part, and a calendering part. Thereafter, the web formed fromthe pulp-as above described, is put through a super-calender, that is to say, a calender. having rolls heated to a temperature of 115 (1., added strength and gloss to the product. Asbestos papers made in accordance with previous processes could not be subjected to the super-calendering step without becoming more brittle and liable to crack so as to tend to make the larger asbestos fibers fall out and thus form perforations in the paper. On the contrary, in the product made in accordance with my invention, the use of the super.calendering step makes the product softer than before the super-calendering treatment.

.While I have described my invention above in detail I wish it tobe understood that many changes may be made therein without departing from the spirit of the same.

I claim:

l. The prooess which comprises forming a paper web from a pulp containing a mineral fiber and a kelp product precipitated therein from alginic acid by a mineral salt adapted to 7 form an insoluble compound therewith, the alginic acid having been pro-..

duced by grinding the kelp with an alkali, neutralizing with an acid, washing, and then removing the water "therefrom. 2-. The process which comprises forming a paper web from a plup containing asbestos and a kelp product precipitated thereinfrom alginic acid by a mineral salt adapted to form an insoluble compound therewith, the alginic acid having been produced by grinding the kelp with an alkali, neutralizing with an acid, washing, and then removing the water therefrom.

'3. The process which comprisesforming a paper web from a pulp containing a mineral fiber and a kelp product precipitated therein from alginic'acid by a mineral salt adapted to form an insoluble compound therewith, the alginic acid having been pro-' so as to give an insoluble compound therewith, the alginic acid having been produced by grinding the kelp with an alkali, neutralizing with an acid, washing, and then removing the water therefrom so as .to form press-cakes.

5. The process which comprises forming a kelp product by grinding the kelpwith an alkali, neutralizing the alkali with an acid, washing, and 7 then ,7 removing thev water therefrom.

6. The process which comprises forming a kelp product by grindingthe kelp with an alkali, neutralizing the alkali with an acid, washing, and then removing the water therefrom in a press to form press-cakes.

7. The process of making paper which comprises treating kelp with an alkali to solubilize the alginic' acid and algulose, c0- agulating with a mineralv acid,-washing to eliminate natural mineral salts, incorporating fiber pulp with the coagulated material and forming paper therefrom. I I

8. A mineral fiber. paperconsisting essen tially of mineral fiber pulp and a kelp product formed from kelp, including its alginic acid and algulose which has been solubilized withan alkali and rendered insoluble with a precipitant. p I

9. An asbestos paper consisting essentially of asbestos fiber and a kelp product formed from kelp, including its alginic acid and algulose which has-been solubilized withan alkali and rendered insoluble with a precipitant. f U V '10. A mineral fiber paper consisting essentially of mineral fiber'pulp and a kelp product v formed from kelp including its alginic acid and algulosewhich has" been solubili zed and then rendered insoluble b the addition. of a'mineral acid.

In testimony that I claim the foregoing, I have hereunto set my hand this l7thday of June, 1927. a

. ARTHURv L. -KENNEDY.

duced by grinding the kelp with an alkali,

neutralizing with an acid, washing, and then removing the water therefrom so as to form press-cakes. V

4. The process which comprises forming a paper web froma pulp containing asbestos and a kelp product precipitated therein from alginic acid by a mineral salt adapted toform 

